This part provides background information related to the present disclosure, which is not necessarily the conventional technology.
With the development and evolution of wireless networks, more and more services are carried by the wireless networks. In this case, additional spectrum resources are required to support transmission of a large amount of data. Cellular wireless network operators start discussing how to use unlicensed spectrum resources such as the 5 GHz ISM (Industrial Scientific Medical) frequency band, on the basis of utilization of the existing LTE (Long Term Evolution) networks. On the other hand, in the WiFi wireless industry, more WiFi systems are deployed on the unlicensed spectrum. Communication systems between different operators and different systems have equal rights to use the unlicensed frequency band. However, different operators and different systems may be interfered with each other when using unlicensed spectrum resources, which results in failed information transmission on one side.
In a WiFi system, a contention window (CW) is one of the effective solutions for resolving the resource conflict. When a transmitting node configured with a contention window is to perform data transmission, the transmitting node needs to randomly select a random number in the range of the contention window as a waiting time period, and transmits data using corresponding resources when the waiting time period elapses. A spectrum management server in the system may set a contention window size (CWS) for each transmitting node according to different requirements, where a greater contention window size corresponds to a smaller probability of using the unlicensed spectrum by the transmitting node, and a smaller contention window size corresponds to a greater probability of using the unlicensed spectrum by the transmitting node. In a system that does not support the contention window, such as an LTE system, a counter may be configured for each transmitting node, which plays a same role as the contention window. When a transmitting node configured with the counter is to perform data transmission, the transmitting node may use a value of the counter as a waiting time period, and transmit data using corresponding resources when the waiting time period elapses. A node on the network side, for example, the base station, may set the value of the counter for each transmitting node according to different requirements, where a greater value of the counter value corresponds to a smaller probability of using the unlicensed spectrum by the transmitting node, and a smaller value of the counter corresponds to a greater probability of using the unlicensed spectrum by the transmitting node.
In addition, during information transmission using the unlicensed spectrum resources, if a hidden node which is outside the sensing range of the transmitting end and thus is invisible to the transmitting end also performs information transmission, the information transmission of the hidden node interferes with the information transmission by the transmitting end, which results in failed information transmission. In order to solve the problem, an energy detection threshold of the transmitting end may be reduced to extend the sensing range of the transmitting end so that the hidden node is sensed and monitored by the transmitting end.
During the information transmission of a node in a wireless communication system operating on the unlicensed band, failed information transmission may occur due to change in quality of a channel between the transmitting end and the receiving end, or due to inference to the receiving end from a hidden node as described above or from other access mechanisms. In the case of the failed information transmission due to the change in quality of the channel between the transmitting end and the receiving end, it is obviously inappropriate to adjust a spectrum sensing parameter, such as the contention window size or the value of the counter. Therefore, it is important to acquire the cause of the failed information transmission.
Therefore, a new wireless communication technology solution is required, with which the cause of the failed information transmission can be acquired, and the spectrum sensing parameter is adjusted only in a case where the cause of the failed information transmission is a non-link quality cause, thereby increasing a probability of successful information transmission between the transmitting end and the receiving end, and avoiding unnecessary adjustment.